I was trying to contrast your point-of-view, that you prefer OS X, in contrast to the fact that there's little empirical evidence that OS X is an outright better model or that there's little evidence that lots of people are going out of their way to imitate it. Sorry if that didn't come across very well.
My personal opinion is that for every advantage that OS X has via its menubar and dock layout it has an equal disadvantage, so both styles are equal.
For example, for the menus at the top gives you the advantage of Fitts' law but makes accessing menus while multitasking and switching between applications and using menus more difficult. Moving from looking at the top of the screen to the window is a further distance, which may make viewing slower. You do get the advantage of a more intuitive MDI applications though.
The dock is better for frequently used applications, but it uses more screen space, the locations of applications in the dock shift as you use it and it uses dramatically more space than the quick-launch bar. It also stylistically makes maximisation look rather 'off'.
If you solely rely on keyboard navigation, Windows-style is probably better - you can easily load an application without the mouse (especially in Vista), plus you primarily use alt+tab/cmd+tab which means that the menu is largely wasted space. If you use many applications, the Start Menu is likely quicker than using Finder, especially on Vista with its built-in search. Of course, there's Quicksilver and their ilk but that's not standard and similar applications are available cross-platform.
Finally, if you believe they're approximately equal, if you're developing a new OS from scratch with no existing users and you have to choose between the two it's probably better to lean to lean towards a Windows-style layout as more people are familiar with it to narrow the learning curve, which would make choosing Windows-style windows as the default a reasonable decision.
I'm certainly not saying this was the thought process at all - let's not forget Mac OS X was years from release when the GNOME and KDE projects were started and they were building on top of the paradigms of existing X applications - but it certainly shows that if you were making the decision today choosing the Windows model would still be a reasonable one, and that's excluding the factors involved in changing like alienating the current user-base.